Virtual GEM provider

modulename: vgem.ko

configname: CONFIG_DRM_VGEM

Linux Kernel Configuration
└─>Device Drivers
└─>Graphics support
└─>Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)
└─>Virtual GEM provider
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Choose this option to get a virtual graphics memory manager,
as used by Mesa's software renderer for enhanced performance.
If M is selected the module will be called vgem.

source code: